A. Field of the Invention
This invention relates to air washers, and more particularly to an air washer with chilled water sprays and additional washer sprays which provide for a constant year-around dewpoint temperature in a conditioned area. Air washers using chilled water find their greatest popularity in large industrial airconditioning installations such as textile and printing plants. Humidity control is important in such plants and the humidity can be adjusted conveniently by changing the temperature of the spray water. The air washer is a reasonably good filter of the air, it can cool the air by inexpensive evaporative cooling when conditions are favorable, and it can heat and humidify in conjunction with heating coils during winter operation.
In textile mills, yarn under tension is transported over high speed spindles and a decrease in the percent relative humidity of the air will cause the yarn to tangle or break or become sticky on the spindle. Such a condition results because of build-up of static electricity caused by the high speed rotation of the spindles. Thus, it is readily apparent that a means for providing constant temperature and humidity in a textile plant or the like is of extreme importance.
B. Brief Description of the Prior Art
It is known in the air washer art to introduce chilled water into an air washer through the washer spray pump suction pipe. The chilled water is sprayed by means of spray nozzles into an air stream which is passed through the air washer. A temperature control on the leaving side of the air washer is used to vary the amount of chilled water supplied to the washer spray pump suction pipe.
When the air washer is to be operated in the summer, chilled water is supplied to the washer spray pump suction pipe for cooling. The following example will illustrate how air can be cooled from a room temperature of 80.degree.F to the required dewpoint of 60.degree. F. Using 10 gpm of spray water per 1000 CFM of air, the chilled water must cool the spray water 4.3.degree.F which gives 55.7.degree.F spray water through which the air passes. EQU 1000 CFM .times. 1.08 .times. 20.degree.F = 21,600 BTU/hr. EQU 10gpm .times. 500 .times. 4.32.degree.F = 21,600 BTU/hr.
Thus, it may be readily appreciated that unless atomizers or external humidifers are used, it is not possible to have a room dewpoint temperature higher than the spray water temperature.
In. U.S. Pat. No. 2,110,203 there is disclosed an air conditioning system in which dehumidification is accomplished without the use of refrigerating system or dehydrating solutions. The dehumidification of air is accomplished by mixing fresh and return air which is then passed through a spaced set of spray nozzles. The result is an air stream having certain portions with a relatively high dewpoint temperature and other portions with a relatively low dry bulb temperature. Intimate commingling of this air stream results in the formation of a fine mist or fog due to the condensation of moisture from that portion of the stream having a relatively high dewpoint temperature. The air stream is then passed through proper eliminator baffles to remove the fog or condensation and the conditioned air is passed to the delivery system. U.S. Pat. No. 2,110,203 does not set forth the novel structure of applicant's invention which maintains room temperature at a constant dewpoint year-around.
An apparatus for controlling humidity is described in U.S. Pat. No. 1,955,406. In this patent, there is disclosed a system by which humidity can be controlled in connection with an air washer by simultaneously varying the surface and the distribution of the spray and, at the same time, modifying the spray temperature so that the latent heat content may be modified without changing the final heat content of the air or the sensible heat content of the air may be modified without changing the final moisture content or latent heat content of the air.
In U.S. Pat. Reissue No. 20,944 there is set forth an air conditioning system directed to an air washer which is used to reduce the absolute humidity of air in industrial processes and for maintaining conditions in auditoriums and other places of public assembly. In this patent, a plurality of manifolds having spray nozzles are arranged in an air washer wherein a partition is used to control the mixing of air into a mixing chamber. There is no disclosure in U.S. Pat. Reissue Pat. No. 20,944 of an apparatus for maintaining constant room dewpoint year-around.
While the above mentioned patents disclose embodiments of an air washer utilizing more than one spray manifold, none of the above patents sets forth a structure in which an initial spray is used to cool the air to a certain wet bulb line, the air then being adiabatically cooled to a desired room dewpoint so that the leaving air is almost 100 percent in a saturated condition. This saturated condition is required in textile mills where yarn is being transported over high speed spindles.